The structure, function and pathology of the circumvallate papilla is being studied in human and other mammalian species by means of biopsy and autopsy specimens. Histologic changes in biopsied circumvallate papillae of dysgeusic and comparable non-dysgeusic control patients are being compared with these patients' taste sensitivity. Facial expression in response to taste stimuli is being studied from videotaped records of healthy young adults eating and drinking foodstuffs with known and graded amounts of tastants. Their facial expressions are being compared with their written hedonic responses to the foodstuffs. A variety of information collected by clinical and laboratory evaluation and questionnaire over the last three years from 50 patients seeking treatment for various oral sensory disorders is being analyzed to better characterize the patient who seeks help for this type of chronic oral disability (pain, glossalgia, xerostomia and dysgeusia). Alteration in taste preference in rats maintained on a Vitamin A deficient diet, or desalivated by pharmacologic and surgical means, is being studied to determine the type of disability that these experimentally-induced abnormalities of the taste mechanism and salivary glands produced.